That, or get the slabs slabbed to certify that they are not tampered with (like the new ANACS slabs) or counterfeit, but then the slab's slabs could be counterfeited. Ah, never mind.
I thought it could be the rivers Cocytus and Pyriphlegethon, which flow into the chief river Acheron. Or maybe the river Lethe, but then if it was that river you wouldn't remember. Just remember to keep one coin as an obol for Cheron.
It's not their ability I question. Not even their ability to un-cover new methods of counterfeiting. I don't believe there is any such thing as the "un-defeatable" counterfeiter any more than I believe their can be an "ultimate weapon." A weapon is ultimate until someone else finds a way to counter it. Then the competition starts all over again, seemingly forever. What I question is their capacity to use their abilities in what seems to me to be an assembly line environment. How many coins can someone look at before they are in "Wally-World?" Maybe the next mantra will be: Don't buy a coin slabbed after 10:00 A.M.